hal: Add support for VoWLAN feature

Add VoWLAN pcm ID and usecase to enable voice
over WLAN feature.

CRs-fixed: 642690
Change-Id: I791ffb19f61a726b8c2c45de380559831e08b520
diff --git a/hal/msm8916/platform.h b/hal/msm8916/platform.h
index cad5198..45df28a 100644
--- a/hal/msm8916/platform.h
+++ b/hal/msm8916/platform.h
@@ -187,6 +187,7 @@
 #define VOICE2_CALL_PCM_DEVICE 13
 #define VOLTE_CALL_PCM_DEVICE 15
 #define QCHAT_CALL_PCM_DEVICE 14
+#define VOWLAN_CALL_PCM_DEVICE 16
 
 #define LIB_CSD_CLIENT "libcsd-client.so"
 /* CSD-CLIENT related functions */